Solvent recovery apparatus



Dea 16, 1941 J. HARMAN-ASHLEY 2,266,031

SOLVENT RECOVERY APPARAT Filed June 15, 1940 up), INVENTOR Jahn,Harmarmslzy ATTORNEYJ SYM am@ M4 .e1

Patented Dec. 16, 1941 UNITED STATES gPATLNT OFFICE 2,266,031 v SOLVENTRECOVERY APPARATUS John Harman-Ashley, Caldwell, N. J.

Application June l5. 1940, Serial No. 340,859

4Claims.

Solvent recovery apparatus is well known by which solvent laden air orgas may be conducted through adsorber tanks or units having solventadsorption beds consisting of so-called activated carbon or the like, abattery of adsorber units being usually used in such manner that whileone unit is in solvent adsorbing ph'ase, steam or other equivalentheating fluid may be passed through the adsorption bed of the otherunit, the solvents thus freed from the latter adsorption unit beingpassed therefrom along with the steam to a condenser and from thence toa decanter where the recovered solvent is separated out. Solventrecovery apparatus of the above type has been used for many purposes andhas been characteristically so complicated and expensive as to beeconomical only where quite large volumes of solvent laden gases were tobe treated.

The present invention relates to solvent recovery apparatus of the abovementioned character and has for one of its objects to provide a solventadsorption bed supporting structure of such construction and relation tothe adsorber tank as to have substantial advantages from the standpointof eniciency and uniformity of action upon the solvent laden gases, ageneral object of the invention being to provide a solvent recoveryapparatus which will be suicently simple and economical in cost, andvyet suiciently efficient in its action to make its use feasible in thedry cleaning industry and other plants where the volume of recoverablesolids is so small that solvent recovery apparatus of the previous typeshas been too costly and complicated to be pracy tical. Among otherobjects the invention aims to provide valve construction for solventrecovery apparatus of the above `character which is improved from thestandpoint of simplicity and cost and yet is eiective in operation.

Further objects and advantages of the invention will be in part obviousand in part specifically referred to in the specication hereinaftercontained which, taken in conjimction with the accompanying drawing.discloses a preferred embodiment thereof; suoli' embodiment, however,should he considered only as illustrative of the principles of theimvenion in its broader aspects. In the drawing- Fig. l is a cenia'alvertical section taken through an admi-ba' unit constrained inaccordanne with ille invention.

E gZisasidedevatiomslmwingapah-cf adjacmt adsorber units, andillnstraimg pre- -m .m to be nserl m connectank I which may be ofcylindrical metal construction, and having a top cover 2 suitablysecured to the body of the tank.

In accordance with one preferred feature of the invention I employ asolvent adsorption bed of what may be termed a dome shaped or basketlikeconfiguration, th'e illustrated solvent adsorption bed 3 which willusually be of activated carbon, being held in position by spaced screenmembers which have dome shaped or hemispherical portions 4 and Erespectively, which are located substantially concentrically one withinthe other, so that the solvent adsorption bed is retained betweenthere.v 'Ih'e solvent laden gases pass through the activated carbon bedfrom one face to the other and a bed of the above construction providespaths of substantially uniform resistance to flow of the gases,irrespective of the particular point at which they may enter thebed. Thearchshapeofth'ebedalsotends to keep it in its original shape withoutsagging or slumping, and a large area of exposure of the gases to thebed is provided with relatively small volume or displacement of the bed.

In the illustrated form of the inventionthe screen members abovereferred to also have upwardly extending annular screen portions la and5a respectively, which are suitably fastened toinner-andouterringslandsecuredtothe cover 2 of th'e tank and afording anannular openings atthetopthroughwhich accessma;r

.bereadllvhadtothesolventadsorpionbedfor purposes of repair orreplacement. These rings 1 and 8 are made imperfcrate, to avoid short'of the gases around the carbon bed.

'Asshovmanannularplateldetachablysecuredfmsintable it a tothe rings and8, normallysealstheactivaiedcarbonbedmom thecuterair.'lhustherbonbezlsupportmg structure is preferably supported or suspmdedfromth'eeoverzofthetankandmaybemmovedn'omthetankalongwiththecoverwhenadsorbedinto the bed 3. lThus the main walls of the tank will not have to bemade of corrosion resisting metal when vapors are being treated whichwhen subjected to steam and carbon migh't act corrosively during thetreatment.

The bed 3 of activated carbon thus divides the interior of tank I intotwo chambers II and I2, into one of which the solvent laden gases to betreated are led, and from the other of which the gases are exhaustedafter giving up their solvent content to the bed 3 while passingtherethrough. In the illustrated form of the invention the solvent ladengases are led into chamber II through an intake conduit I3 passingthrough an opening I4 in the cover 2 of the tank, and after passingthrough` the bed 3 the gases are exhausted by means of offtake pipe I5passing through an opening I6 in the bottom wall of tank I. bed 3 may beled into chamber I2 by suitable pipe I1 having a valve I8 therein, andthe steam carrying the solvents freed from the bed 3 may be led to acondenser (not shown) by a pipe I9 having a valve 20 therein. Condensatecollecting within tank I may be drawn off through a pipe 2I connected tothe bottom of the tank and leading toa suitable condensate trapindicated diagrammatically at 22.

The valves I8 and 20 of courseare closed during the adsorption phase inwhich conduits I3 and I are open, and in the bed'heating phase in whichthe solvents'are freed from the bed, the conduits I3 and I5 are closedoff fromthe ad- Steam for separating the solvents from` pneumaticcylinders 40 and 4|. The opposite ends of the rocking lever are likewisecoupled respectively by connecting rod 42 to piston 43 operating inpneumatic cylinder 40, and a connecting rod 44 connected to piston 45operating in pneumatic cylinder 4I.

By suitable pilot valve mechanism (not illustrated or described indetail since suitable forms thereof are well known) fluid under pressuremay be admitted and exhausted selectively from cylinders and 4I, toposition the plate valves 23 ternatively the valve operating mechanismshown sorption tank I, valves I8 and 20 being 'then open. The valvemechanisms for opening and closing communication between conduits I3 andI5, and the interior of tank I, preferably utilize plate members 23 and24 located respectively in the chambers II and I2, and seatingrespectively (with appropriate interposed packing not shown or describedin detail) against the in"- wardly projecting annular. walls 25 and 25,ex-

tending respectively from conduits I3 and I5 into-the interior of tankI. Thus the positive pressures existing within chambers II and I2 duringthe phase of operation when valve members 23 and 24 are closed, assistin firmly sealing these valve members against the valve seatsconstituted by members 25 and 26. The valve plates 23 and 24 may bemoved by actuating rods 21 and 28 respectively within the conduits I3and I5.

In Figs. 2 to 4 I have shown more in detail suitable valve operatingmechanism for controlling the valves 23 and 24. Fig. 2 shcws a pair ofadsorbent units each consisting of a tank I and associated partspreviously described, connected to solvent laden gas intake conduit I3and e'xhaust gas conduit I5. As shown in Fig. 2 the plate valveactuating rod 21 may be pivoted to a walking beam 29 located in theconduit I3 and connected 'to an oscillating shaft 38 suitably journalledinsuch conduit. The actuating rod 28 of the plate valve 24 is likewisepivoted to a similar walking beam 3l located in exhaust gas conduit I5and fixed to .an oscillating shaft 32 suitably journaled in said.conduit. Now referring 4) to-pistons 3l and 39 operating respectively indiagrammatically in Fig. 4, may be set in the opposite position whereinvalves 23 and 24 of the tank I at the right of Fig. 2 will be open, andvf the corresponding valves of the tank I at the left of Fig. 2 closed.'I'he valve members and their incorporated directly into the' tankstructure proper, using a simple form of plate valve located insde ofthe tank and so related to its valve seat that the interior' pressureassists in' maintaining a seal when the valve is in closed position. Ialso prefer to use in conjunction with the valve plates 23 and 24, anauxiliary valve mechanism which serves to equalize the pressures onopposite sides of the valve plate when the latter is to be moved to openposition. As exemplified in Fig. 5, the valve rod 2`8 may extend througha hole 46 in the plate valve 24, being pr'ovided with an enlarged head41 adapted to seat (with appropriate interposed packing not shown or.described in detail) against the opposite face of plate valve 24 whenthe valve is in closed position. ^As shown in Fig. 5 the valve. rod 28is also provided with a collar 48 which engages against the undersurface of plate valve 24 after the valve rod 28 has been lifted to aslight extent,and removes the valve plate 24 from its seat. The initialmovement of rod 28 opens the hole 46 through valve plate 24 and thusequalizes pressure on opposite sides 'of the valve plate before thelatter is moved from closed position. The valve areas in apparatus ofthe type under discussion are necessarily relatively large, and in theabove way simple plate valves may be actuated without undue strains orexpenditure of power, and effectively sealed when closed, avoiding theextra space-and expense of exterior valve constructions of the typeheretofore employed in similar apparatus.

While the invention has been disclosed as to solvent recovery apparatusof a particular specic construction,it should be understood that manychanges may be made therein withoutdeparting from the invention in itsbroader aspects, within the scope of the appended claims.

I claim: y

1. Solvent recovery apparatus of the class described having a tank, anda solvent adsorption bed supporting structure including spaced screenmembers within said tank and having portions of substantially inverteddome shaped configuration and position, said dome shaped portions beingsubstantially concentrically disposed, and

valve mechanisms for admitting into and exhausting gases lfrom withinsaid tank, one ofof said valve mechanisms communicating with the spacewithout said dome shaped portions,

said screen members being suspended from parts,

located at theupper portion of the tank in" spaced relation to the sideand bottom walls of the tank, whereby the inverted dome shape of saidscreen members largely supports the weight of the adsorptive bed withoutsubstantial sagging or slumping of said screen members.

2.' Solvent recovery apparatus of the class described having a tank, anda solvent adsorption bed supporting structure including spaced screenmembers within said tank and having portions of substantially inverteddome shaped coniiguration and position, said dome shaped portions beingsubstantially `concentrically disposed, and valve mechanisms foradmitting into and exhausting gases from within said tank, one of saidvalve mechanisms communicating with space within said dome shapedportions and the other of said valve mechanisms communicating with thespace without said dome shaped portions, said bed supporting structurealso having annularportions tion and position and having end and sidewalls substantially uniformly spaced, and valve mechaand bottom walls ofthe tank, whereby the inverted dome shape of said screen members largelysupports the weight of the adsorptive bed without substantial sagging orslumping of said screen members.

4. Solvent recovery apparatus of the class described having a tank and asolvent adsorption portingstructure including spaced screen bed mem sone surrounding the other and located within said tank, said screenmembers being l substantially of inverted dome-shaped configuextendingupwardly from said domek shaped portions to the top of the tank toprovide a llng opening for said bed, said screen members being suspendedfrom parts located at the upper portion of the tank in spaced relationto the side and bottom walls of the tank, whereby the inverted domeshape of said screen members largely SllPPOrts the weight of theadsorptive bedwithout substantial sagging or slumping of said screenmembers.

3. Solvent recovery apparatus of the class described having a tank and asolvent adsorption b ed supporting structure including spaced screen Vesmembers one surrounding the other and located within said tank, saidscreen members being sub- .stantially ofinverted dome-shapedconguraration and position and having .end and side -walls substantiallyuniformly spaced, and Vvalve mechanisms for admitting into andexhausting gases from within said tank, one of said valve mechanismsincluding a valveseat and valve member located withinthe space enclosedby said screen members and the other of said valve mechanismscommunicating with the space without said screen members, said Lvalvemember comprising a plate movable'downwardly within the space enclosedby the inner of said screen -members to uncover its valve seat, and anactuating member for said valve plate which' extends upwardly to thespace above said screen members.

JOHN HARMAN-ASHLEY.

